Conventional sound speaker systems are known which attempt to provide omni-directional sound by incorporating a stationary speaker and a turning speaker assembly located within a housing. It is conventional for high-frequency audio to emanate from the turning speaker assembly and the low-frequency audio to emanate from the stationary speaker. This is to accomplish an omni-directional and tremolo effect for the system. See for example U.S. Pat. Nos. 3,483,945; 2,887,000; and 2,995,054.
These known conventional systems are not free of problems. For example, in order to achieve the tremolo effect, multiple speakers are provided on a rotating drum or other equivalent arrangement which in certain size rooms causes unwanted standing waves that are particularly displeasing to the audience and to the performer. Another serious disadvantage is that these conventional systems are sensitive to unwanted feedback which will produce a high-pitch whistle or other unpleasant piercing sound until the pick-up microphone is removed from the speaker area. A still further disadvantage of the known systems is that a plurality of speakers must be used in the turning assembly in order to produce the tremolo effect. To avoid unwanted shaft vibrations, these speakers are either arranged in a drum-like configuration centered upon a central shaft or axis or, alternatively, a single speaker is provided with a counterweight or counterbalance to avoid the shaft vibrations. These arrangements necessarily increase the strength requirements and complexity of the support and bearing system for the respective support shafts. Furthermore, the multi-speaker rotating arrangement must be symmetrically arranged such that all speakers must rotate together and at the same speed and thereby they cannot interact one with another.